It makes perfect sense. And actually, that suggestion I made might not always be very appropriate. If the images are loaded into video memory, they can potentially be blited faster using the hardware, and that likely only supports rectangles. Plus existing APIs such as the Windows API likely only supports rectangles. But, it all depends on whether your doing software or hardware biltting, and whether or not you want to make use of existing APIs. What I suggested might be faster for a software approach where you're not using an existing API, since it'll need to touch noticably less memory. It also saves on memory.
So, now that we have that out of the way, Big Game Hunters. Yeah, I suppose Starcraft maps could potentially be imported into OP2 format then. You'd have to figure out some kind of cell type translation/default though, and figure out what to do about tubes, bulldozed tiles, scorch marks, walls, etc. Certainly some graphics editing is involved.